1. Field of the Invention
The present invention relates to picture displaying method and apparatus of a personal information terminal such as PDA (Personal Digital Assistant), more particularly, to method and apparatus of displaying a picture if a personal information terminal is in power-off mode or in nonuse state when an external AC power is being supplied.
2. Description of the Related Art
A lately-developed PDA, which is being widely used, has a variety of functions such as private schedule management, calculator, electronic notepad, and MP3-formatted audio data player.
The small-sized PDA is easy to carry and it has a relatively wide LCD for its small size and a touch screen as an input device. A user carrying the PDA can check or confirm necessary information through the wide LCD easily and enter data or choose a desired function through the touch screen.
And, the PDA equips with a rechargeable battery which is conveniently charged through an additional AC charging cradle while the PDA is placed thereon. The rechargeable battery supplies an electric energy for the PDA while it is carried by a user.
The personal information terminal such as PDA, in general, conducts a power save operation to reduce power consumption. In conducting a power save operation, conditions such as time determining when to enter a power save mode are necessary. FIG. 1 shows an illustrative menu screen for setting power save mode entering periods. The time 101 set in the ‘On Battery Power’ item specifies that the system should enter a power save mode if the personal information terminal is continuously unused during the time 101 under the condition that a rechargeable battery supplies an electric energy. The time 102 set in the ‘On External Power’ item indicates that the system should enter a power save mode if continuously unused during the time 102 under the condition that an external power is fed.
In a power save mode, elements consuming much electric energy, e.g., an LCD backlight is turned off. The operation-suspended elements are turned on again on an input.
And, even though a user touches an On/Off button to turn off the personal information terminal, the power supply from a battery or an external AC power for internal elements is not completely cut off. Instead, the operation mode is changed to operation-suspended state, namely, power save mode. Thus, the personal information terminal can still detect in a power-off state whether there is an input, e.g., data inputs or AC power supply.
As explained above, the personal information terminal changes its operation mode to power save mode if any input is not entered for a predetermined time even under the condition that an external AC power is supplied, and returns to normal operation mode, namely, power-on state the moment any input is detected.
However, the personal information terminal with such a function of power save operation can not be used for other purpose, e.g., a picture frame.